Sleeping by the gate

[Flossylu]

Hello! Looking for advice.

We've recently moved my little girl (21months) into her cot bed with the side down. Whilst perhaps a little early we need her to transition t sharing a room with her brother and she's a climber so will definitely climb out her cot to get to him.
The first night she didn't even attempt to get out the bed.
But every night since she has fallen asleep at the baby gate. She is not unhappy or upset AT ALL. she reads a few books by herself then gets her Teddies, puts her bum in the air and falls asleep by the gate. Then 30mins later we transfer her to her bed where she stays all night apart from typically 1 wake up which we can't seem to drop (any advice on that too would be amazing!) where she needs a tiny amount of milk to go to sleep (literally 3oz).

Having her sleeping by the door isn't practical long term (especially with the room share approaching) and in the day she is now refusing to nap at all and just reads and plays until nap time is over- and she used to loveeeee her nap!

So tonight we did the 100 walks method of putting her to bed. And she did get sad which broke my heart a little 😔😔 but 40mins later she is fast asleep in her bed.... How many nights do we have to do this and is this the only way??

Thank you for any help you can offer!